Microsoft celebrates summer this week not with a Slip 'N Slide or a barbecue, but with stylized colorful multiplayer, organized crime, and Hannah Montana.

Leading the pack this week is Uber Entertainment's class-based, stylized third-person shooter Monday Night Combat (1,200 MS points, or $15). Set to debut this Wednesday, the Xbox Live-exclusive shooter blends fast-paced combat with a significant strategy component. The title is the fourth in Microsoft's five-game Summer of Arcade promotion, which culminates next week with the feature-stripped Lara Croft and the Guardian of Light. Despite its name, you can play the game any evening of the week.

Switching to the demo front, 2K's '40s and '50s crime action sequel, Mafia II, now has a sampler available for gamers to download. The game casts players as Vito, an up-and-coming member of the Mafia in Empire Bay. The sampler thrusts players into Vito's first serious assignment, where he'll need to "get the job done" by whatever means necessary.

Microsoft's virtual store added three new Xbox 360 downloadable titles this week, the most prominent of which is Tom Clancy's H.A.W.X. ($29.99). The arcade flight combat game puts players into the cockpit of a futuristic jet fighter lighting up enemy forces.

Also now available for download is Juiced 2: Hot Import Nights ($19.99). The sequel to 2005's original, Juiced 2 offers gamers arcade-style racing, an online career mode, and a user-specific Driver DNA system, which tracks a player's driving habits. Additionally, Deal or No Deal model Ursula Mayes sits atop the game's box art.

The last title added to Microsoft's full-game download hub this week is Disney Sing It: High School Musical 3: Senior Year ($29.99). The teenage singing game features songs from Disney's original High School Musical, its sequel, and the third installment.